South Africa's Stephen Mokoka broke the men's 50km record in his first race at the distance.
The 37-year-old won the Nedbank Runified 50km (31 miles) in Gqeberha in two hours 40 minutes 13 seconds, beating the time of 2:42:07 set by Ethiopia's Ketema Negasa last year.
Mokoka competed in the marathon at the 2012 and 2020 Olympics and 10,000m at the 2016 Olympics.
"I'm tired. It's a long way, but I enjoyed it," he said.
World Athletics added the 50km distance to the list of events for which world records are recognised in July.
Ethiopia's Amelework Fikadu Bosho dominated the women's race to win in 3:04:58, almost four minutes ahead of second place but 34 seconds short of the world record.
Meanwhile, double Olympic marathon champion Eliud Kipchoge won on his Tokyo Marathon debut in 2:02:40, while fellow Kenyan world record holder Brigid Kosgei won the women's race in 2:16:02.